Maybe the most important question is how much people care about this.
Let's say you were playing a mission and you were being referred to by [Rank], rather than Captain. Is that going to totally ruin your experience? Suppose the mission is great otherwise, would you seriously rate it lower due to being referred to by [Rank], or would you just ignore it as a minor annoyance?
I think that like with everything else this depends on what character is addressing the player, and whether or not it makes sense with that character's 'voice.'